Field of Invention
The present invention relates to a pair of pruning shears with multi-stage actions for cutting branches with larger diameters, especially to a pair of pruning shears with multi-stage actions for cutting branches whose diameter is larger than 30 mm. By multi-stage actions, the force required for cutting the branch is given at different stages.
Description of Related Arts
Generally pruning shears are used for cutting and trimming branches of trees and flowers to improve the environment and accelerate growth of flowers and plants. Most of plants around the house are small shrubs. In order to improve air quality and living environment, many people starts to plant large trees and flowers, even large fruit trees. The branches and leaves of trees/flowers are grown and scattered. Thus proper pruning is required. Moreover, when a typhoon hits or bad weather comes, the branches may be broken and crashed to cause damage to nearby homes and people. Thus tree trimming and pruning is required at times for growing and beauty of the trees and for the safety. The diameter of most branches of the large trees is larger than 30 mm. It's difficult to cut the branch once by general pruning shears.
Refer to Taiwanese Pat. TW M356376, a pair of pruning shears with multi-stage action is revealed. The pruning shears include a fixing base, two moveable seats, a cutting blade, a blade spring, a stopping hooked rod, two support pieces, two support springs and two protection covers. The fixing base is formed by two corresponding bases. A blunt part is disposed on an upper part of the fixing base while a first pivoting hole is arranged at a front surface and a second pivoting hole is mounted at a rear surface of a middle part of the fixing base. The first pivoting hole is used together with a first pivoting rod and the second pivoting hole is used in combination with a second pivoting rod. A long insertion hole is set at a center of the fixing base. A lower part of the fixing base is disposed with a fixing part, a connecting hole and a connecting handle extended thereof. The fixing part is used together with a fixing pin while the connecting hole is used with a connecting rod. An upper part of the moveable seat is arranged with a second pivoting hole, a curved adjustment hole in front of the second pivoting hole, and a connecting handle extended from a lower part thereof. A blade corresponding to the blunt part of the fixing base is disposed on an upper part of the cutting blade. A first pivoting hole and a first fixing part are arranged at a middle part of the cutting blade while a plurality of one-direction locking teeth is set on a lower part of the cutting blade. The locking teeth are arranged in a curved manner. The stopping hooked rod includes a second fixing part set in front of a lower part thereof, a connecting hole on a center thereof, a leaning part disposed on a rear side and close to an upper part thereof, and a fastening hook arranged at the upper part hereof. A third fixing part is disposed on an edge at the top side of the support piece while a fastening hole corresponding to a fixing rod is mounted on a bottom side thereof. A housing chamber with the same shape of the insertion hole of the fixing base is projecting from the protection cover. A fourth fixing part is disposed in one side of an upper part of the housing chamber while an assembly hole corresponding to the first pivoting hole and the connecting hole of the fixing base is arranged outside the fixing chamber.
The above pruning shears are used for gardening and acted at multiple stages. The moveable seats are used in combination with the fixing rod to drive the cutting blade so that a part of the locking teeth is moved for cutting. When the cutting blade and the fixing rod are turned back for next stage of cutting, they are fixed by fastening hook of the stopping hooked rod. Thus the cutting blade will not be opened. Then the moveable seats and the fixing rod drive the locking teeth to move at the next stage. The cutting is finished at multiple stages by repeating the above process and the force applied is maintained at the same level. The cutting is easily completed by the force applied to the same cutting site at several times.
However, during the movement of the cutting blade being driven to open, the cutting blade is always opened over a certain angle. In other words, the first stage action is for opening the cutting blade completely so that a driving handle should be opened to the maximum angle and the maximum distance between the blade and the blunt part is achieved. While performing the second stage, the third stage and the fourth stage of cutting, the blade is gradually opened. Thus the angle between the blade and the blunt part being driven to be opened at the second stage and the third stage should be no more than the angle opened at the first stage. Otherwise, the pruning shears become back to the completely opened mode between the blade and the blunt part at the first stage. Moreover, the movement of the blade at each stage is too long so that users waste much force during multiple stages of movement.